Session 3 Flashcards
Routing,
If you are trying to reach a web server outside your network… the Packet will be destined to what address but the Frame will have whos MAC?
Packet - Web server IP
Frame - Your default gateway mac
Do you have to have an exact match in your routing table?
No it does not have. It could have a 0.0.0.0/0 - which means any network or default route
when a router is moving a packet to another device, what does it change
It changes the frame since now it puts its MAC as the source and the destination of its next hope as destination mac.
what command do you use on the router to show the arp cache ?
show ip arp.
what is 10000000 in decimal?
128
what is 11000000 in decimal?
192
what is 11100000 in decimal?
224
what is 11110000 in decimal?
240
what is 11111000 in decimal?
248
what is 11111100 in decimal?
252
what is 11111110 in decimal?
254
what is 11111111 in decimal?
255
Directly connected address in your routing table means what?
there is an IP address assigned to an interface.
can you set up 2 interfaces on a router going to the same network?
at first it will says OVERLAP.. but you can force it but IT WILL CAUSE ROUTING ISSUES.. DONT DO IT
What can be troubleshooting questions you can ask if a route is not in the routing table of a switch?
- Is it directly connected to the router meaning is there an IP address assigned to a interface.
- Is the interface up. it has to be up to be shown in the routing table.
Local route is what?
a very specific route that points to the actual network interface.
The local route describes the IP address as a host. It make decisions destined to the router faster (telnet or ssh)
matches the ip address of router interfaces.
Ripv2 uses what algorithm and metric
Distance Vector and Hop Count
what is an Autonomous System (AS)
a collection of networks overseen by 1 organization.
what is IGP
interior Gateway protocol - focus on learning routes within 1 local autonomous system
what is EGP
exterior gateway protocol - exchanges information from on Autonomous system with another.
how do routers learn which route to add to the routing table if it learned it from multiple sources?
it uses Administrative Distances
how can you define administrative distance?
is is the reliability of the route source.
connected protocol have an administrative distance of?
0
static protocol have an administrative distance of?
1
eBGP protocol have an administrative distance of?
20
EIGRP protocol have an administrative distance of?
90
OSPF protocol have an administrative distance of?
110
Rip v1 and v2 protocol have an administrative distance of?
120
External EIGRP protocol have an administrative distance of?
170
iBGP protocol have an administrative distance of?
200
what metric does EIGRP use?
lowest bandwidth and delay
what metric does OSPF use?
Total cost
what metrics does BGP use?
attributes
Explain Distance Vector?
Is like when traveling down a road and you see a sign New york -next right. etc
Not a lot of details just know that to get to the destination you have to take this route.
Explain Link State algorithm?
This is like when we use a GPS. the packet has all the necessary details to get to its destination.
Routers determine best source using what?
Administrative Distances. The best # gets adding to the routing table.
Routing source administrative distance
Connected?
= 0
You cannot get better than a connected device to your router
Routing source administrative distance.
static
in order to get to this network - an admin has to put this in the router.
= 1
Routing source administrative distance.
eBGP
= 20
Routing source administrative distance.
EIGRP
= 90
Routing source administrative distance.
OSPF
= 110
Routing source administrative distance.
Rip v1 and v2
= 120
Routing source administrative distance.
External EIGRP
=170
Routing source administrative distance.
iBGP
=200
How do you find an IP of a neighboring device if you are not given the IP address
show cdp n detail
or ping 255.255.255.255
what is proxy arp?
allows a router to response on behalf of an address if it can get you to an address.
floating static routes?
is having a back up static route if the primary fails.
by default it will do load balancing but the way to just change it to just use it if primary fails. you need to change the administrative distance.
When you change the administrative distance to a higher number it will be removed from the routing table since the routing table only shows the best route with the administrative distance.
what are things to check if a static route is not visible on the routing table?
see if there is a connected route since connected routes are better than static
can you reach the next hop address? It needs to be able to reach the next hop. See if the interfaces on the other side is down.
Di you put the right IP address for the next hop.
